Activity in the wireless Internet market is frenetic. Spurred by projections that data services will account for about 25 percent of the wireless telephone market by 2003, or $3 billion to $6 billion, wireless providers are polishing up their products.

In September, Sprint PCS introduced Wireless Web, a service bundle of e-mail and Web news content from Yahoo Inc. via a wireless Web browser in a digital handset. The services are available to most mobile users in the carrier's nationwide territory.

The right coast

In November, Bell Atlantic Mobile launched Web Access for mobile users on the East Coast. The company sells a Web-enabled digital phone for Web surfing, stock quotes, e-mail and managing Web pages.

In July, AirTouch Cellular of Bellevue, Wash., launched NetAccess, an all-digital service that works with data-ready digital phones in Michigan, Salt Lake City and Seattle. Other wireless companies are still testing their Internet services.

In November, GTE Wireless of Atlanta announced a partnership with @mobile.com Inc. of Bellevue, Wash., to provide Internet content from selected Web sites to customers in the San Francisco Bay area before rolling out the service nationwide.

Also in November, US West Wireless LLC announced an initial set of Web wireless services with six categories of available information. Web-to-Go services for general Web access will become available this year.

The NewPoint phone, customized for Sprint's PCS network, has a built-in browser.

More companies are considering the wireless Internet market. Microsoft Corp. has invested $600 million in Nextel Communications Inc. of Reston, Va., to develop custom services using the MSN Internet portal and Nextel phones.

3Com Corp. of Santa Clara, Calif., and Aether Technologies of Owings Mills, Md., announced a partnership called Open Sky. The company will bring voice and data access to users of the Palm VII and other handheld computers via Net-ready phones.

Officials of 3Com know that, although its Palm is the leading handheld, data-only wireless services will not survive for long against onrushing voice and data Web services.

Some cellular equipment and service providers holding contracts with the General Services Administration's Federal Technology Service are unsure how to manage the cutting-edge technology for federal users.

A spokesman for the Federal Wireless Telecommunications Services program said FWTS does not provide Internet data services except for limited Cellular Digital Packet Data (CDPD), and he knew of no plans to develop them.

But feds eventually will find these services available from GSA, FTS commissioner Dennis Fischer said. 'If it is wireless and it communicates, it should be made available to federal customers.'

April Ramey, director of the FTS Innovation Center said, 'We want to be as close as we can to the wireless explosion.' As soon as products and services become commercially available, feds should get them, Ramey said.

For example, a federal organization can buy the same wireless Net services that individuals and businesses can, as long as the services adhere to standard GSA pricing rules, she said. Some caveats apply, however, before federal users plunge into wireless vendors' service plans or Internet-ready handsets.

A confusing variety of technologies for wireless data networks and handsets exists:

''Code-division multiple access (CDMA) is a spread-spectrum ap-proach in which each digital conversation has a code deciphered by the handsets to match the parties at either end.

''Time-division multiple access allocates unique time slots to each user within each channel, letting a large number of users access a signal without cross talk.

''Global standard for mobile (GSM) is a time-division standard common in Europe and the Middle East and coming into use in the United States.

''Narrow-bandwidth advanced mobile phone service (N-AMPS) is a modified version of AMPS that uses a narrow signal.

''CDPD sends dedicated digital signals over cellular networks.

''There are also vendor-specific networks'such as the 900-MHz iDEN and Mobitex networks'to reckon with.

Because wireless network vendors and handset makers seldom make clear which technology they support, users find it difficult to choose a system that best meets their needs.

With WML, limited text content can travel to and from a WML-enabled Web site and a WML-enabled handset. Eventually, the WAP standards will allow communications among various wireless protocols, such as CDMA and GSM, and communications among dissimilar devices such as personal digital assistants, handheld devices and wireless handsets. But the standards are incomplete and cannot ensure compatibility among networks, handsets and other wireless equipment.

Slow spread

Because many vendors' wireless data products are in the trial stage, their availability is limited. Even vendors promising national coverage might be slow in bringing wireless Internet to all users. Roaming is not always an option.

Handsets, optimized for particular wireless networks, generally work on only that network. Wireless data networks and handsets supply top bandwidth of 14.4 Kbps, which is inadequate for serious Web browsing. That is why text information is the most you can get, even from a WAP-enabled site.

Wireless vendors are already promoting third-generation,wireless technology with 2-Mbps data throughput'much faster than PC Web surfing. But the technology will take years to hit the street.

Sprint PCS, AirTouch Cellular, Bell Atlantic Mobile and others have announced tentative trials for interim standards capable of boosting the present 14.4-Kbps throughput by 10 times or more.'Limited screen size and memory also are drawbacks. Few users will be satisfied scrolling through text on the matchbook-sized screens of digital handsets. Some models link to a notebook PC's serial port to give users a larger viewing option.

The throughput of today's wireless Net systems also imposes limits on the information content. Federal users could not justify a wireless Net purchase for noncritical data such as sports scores or local weather, say.

Eddie Hold, senior analyst for Current Analysis Inc., a market research company in Sterling, Va., said, Internet wireless providers have failed to address the fundamental question: 'What is the content that will work well on this platform?'

That issue aside, Hold said, the wireless Internet train is pulling into the station and will become a viable communications tool.